package com.cm;

import java.util.HashSet;
import java.util.Iterator;

/**
 * ClassName:  E
 * Package: com.cm
 * Description:
 *
 * @Author:
 * @Create: 2025/9/12  16:51
 * @Version 1.0
 */
public class E {


    public static void main(String[] args) {
        HashSet<String> set = new HashSet<String>();
        String s1 = "abc";
        String s2 = "def";
        String s3 = "";
        set.add(s1);
        set.add(s2);
        set.add(s1);
        set.add(s2);
        Iterator<String> i = set.iterator();
        while (i.hasNext()) {
            s3 += i.next();
        }
        System.out.println(s3);
    }    }

